How can I do glowing halo particles/special effects in Cycles?
I was working on this clock anyway... Now it glows.

I moved the clocks “Bells” to layer 4 (It could be any other layer than the layer the clock mesh is on. In my case layer 1). I gave the bells mesh a material with “Emission”.

Then in the “Render Layers” panel I added a render layer and selected layer 4 and named it “Glow”. Although you don’t need to rename it.



Here's the node set up in the Compositor.